Aeroplane.



0. HEHMANSON,

AEROPLANE.

APPLICATION FILED SEPT- 25. 1915.

1,201,182., Patented 0%.10, 1916.

2 SHEETS-SHEET l- Fig.1. F1 2.

Fig 5.

0. HERMANSON.

AEROPLANE.

APPLICATION FILED SEPT-251915.

1,201,182. I I v Patented Oct. 10, 1916.

2 SHEETS-SHEET 2.

yQ/TNEss S Wfl W //v VENTQR OSCAR nnmuanrson, or NEW YORK, N. Y.

AEROPLANE.

Specification of Letters Iatent.

Patented Oct, to, 191e,

Application fi led September 25, 1915. Serial No. 53,150.

To all whom it may concern;

Be it known, that I, OSCAR HERMANSON, a citizen of the United States, and resident of the borough of Manhattan,- in'the city, the county, "and the State of New. York, have invented new and useful Improvements on Aeroplanes, of which the following is of the supporting member showing adju'st-.

able blades.

Through experiments made by members of the- Aeronautical Society of America it recently has been ascertained that the air in the wake of a soaring aeroplane, excluding the turbulance caused by propellers, constitutes a locally sequestered and structurally confined congestion, remaining stationary in relation tothe moving plane, so far as it is not distorted by lateral wind. In a' paper read before the said; society in June last Mr. Chas. R. Wittemann sketches this congestion as shown in diagram Fig. 1, and describes it as a wave, forming a vacuum at A, then passing on ina rising quiver B and then into a steady 'and' powerful stream C. This is the first tangible'ac count on the condition of the air following the soaring planes, while all former descrip-' tions I have met merely reflected fancies of observers, but I doubted, if Mr. Wittemann had observed the described congestion following a single plane, that with a biplane the two superposed congestions should be of almost identical shape, because I had a notion that the air deflected at the upper plane in the rear would rush downward into the rarefied stratum above the lower plane,

thereby merging the two superposed congestions. However, Mr. Chas. W. Howell who has carefully studied the matter in his laboratory, is positive that no such merging occurs, proving it by a streamer d which, placed in the center, floats horizontally showing that no current of air crosses the horizontal plane, and that each congestion separately conserves its individual shape. Therefore the disturbance of the air, caused by the soaring plane, appears to be confined to the described congestion following the plane, while the air outside the well marked boundary of it remains practically undisturbed. This is similar to the wake of a ship which in smooth water can be seen trailing for miles, while the surrounding surface of the sea shineslike a mirror, but a difference between the wake of a floating ship and the wake of the soaring aeroplane is remarkable in their duration, because the former continues for a considerable time, while the latter is quickly disappearing, in a measure as the kinetic energy of its com.- motion becomes dissipated in the surrounding air.

Considering a biplane driven by a three hundred horse power motor and assuming that one third of the power is lost in the motor and by friction, and that both planes are of equal service, then each of them will consume a hundred horse power and all this power is absorbed in the commotionof the air following the plane in the aforedescribed' congestion. This power aniounts to 100x 33,000=3,000,000 foot pounds per minute and remains as kinetic energy of the commotion of the air confined in the congestion until it isdissipated at its boundary in the surrounding air. Because this power is completely lost and there must be a considerable amount of avoidable waste of power, since a vehicle of the same resistance to the air as an aeroplane oifers, can be'moved on the ground with the same speed with muclrless power, the" question arises in what form the kinetic energy is stored in the afore described con-V gestion, and if we are able to elicit its-form, the practical problem results, .-to reclaim as much as may be possible of that energy tied up within the congestion.

The'first question I already have tried to answer in a paper presented to the afore said Aeronautical Society, wherein, in order to reveal'the internal formation of the said congestion, I started with the analysis of the tail C, which has been described by Mr.

. Wittemann as a steady and powerful stream of air. I

In the first place, it cannot be a stream because that means it would have a velocity with regard to the surrounding air, which is v impossible because if the particles of air constituting the tail C would have this velocity, they must have had it already while on their passage in B, but in B all particles are undulating in a transversal wave which exeludes the motion in a longitudinal direction. If therefore Mr. Wittemann, in spite of the absence of any longitudinal motion, observed a steady and-powerful commotion in the portion 0, he would better call it a streak instead of stream, and this commotion can only consist of undulatory vibramann has sketched this portion of the comtltl motion as a rather irregular quiver as he has observed it by means of smoke and saw dust fed into that space, but considering the steady and stable character of the whole congestion, such an irregularity is excluded and what ther appears in B must be a train of transversa-l waves wherein the particles of air move vertically up and down while the whole apparition continues to follow the moving aeroplane, thereby gaining thea pearance of a longitudinal propagation for the waves, with decreasing amplitudes from A toward 0. I

Coming now to A, it is plain that Mr. Wittemanns sketch of the taper cannot be correct. Here at the junction of B and A his means of observation no longer were operative because the vibration'of the undulatory commotion was too violent to carry smoke or other visible particles visibly along. Mr. Wittemann calls the whole space A a vacuum and Mr. Howell, who has checked Mr. Wittemanns experiments with men-carrying aeroplanes in his laboratory with small models in a current of compressed air, told me that this vacuum has been ascertained by actual tests. lhe existence of this-vacuum within the space A proves the violence of the commotion of the air, in fact, according to the law of Bernoulli, it we. could estimate the integral reduction of pressure of the air throughout the whole space A, below the barometric pressure of the air outside, this deficit of pressure multiplied by the volume of the space, directly measures the amount of free kinetic energy within that space, which must be the amount of kinetic energy afore estimated. Considering this large amount of kinetic energy we now must form an idea of the kind of commotion for the air within the space A.

There are only two essentlally d'ifi'erent forms for such a commotion we know of: In

tinned to exhibit for many years, we'know that eddies are formed in front and in the rear of bodies movingin water with a speed which is too great to let the water stream stated large amount of kinetic-energy within that place can be found, nor is it possible tounderstand how such eddies back of the space A suddenly should be converted into transversal waves appearing in B. On the other hand it is easily realized that all conditions for theformation and for the maintenance of transversal wavesare present in that space A.

' Looking at the trailing edge of the aeroplane, it must be understood that above that.

edge the air is rarefied when the aeroplane soars, while below the edge the air is compressed. Consequently the compressed air will rush around that edge upward, but since the plane is moving forward it leaves the rising current of air behind and this current continues to rise until by compression its motion is stopped, because the outside air has a relative'speed, equal to that of the moving plane, and consequently a coinmensurate momentumthat must be overcome by the rising current. The instant this current is stopped, all the air within it is compressed and will expand now flowing downward, and since the trailing edge of the aeroplane is out of its way, it will rush down past the edge until it again is stopped by compression at the lower boundary of the space A, whence it rebounds and again rushes upward, while 'in the meantime new waves have started at the trailing edge of the soaring aeroplane. The production of these waves is to some extent similar to that of the waves produced by blowing a flute, and since all the conditions forthe formation and-for the maintenance of such transversal waves are present within the space A,

and no other form of commotion for the air within. that space is imaginable that could represent an equivalent amount of kinetic energy, I claim that the whole space A is filled with transversal vertical waves that have their nodular surfaces in the upper and in the lower boundaries of that space A, and that the same waves continue visibly in the 'space E with reduced amplitudes, and farther down in C again invisibly, with still further reduced amplitudes, until eventually the kinetic energy of the agitated air is re duced to the normal molecular kinetic energy of the surrounding air. If my explanation of this remarkable and highly important pnenomenon is correct, the sketches furnished by Mr. Wittemann will have to be so corrected that there is no discontinuous transit from A toB, and further exploration of the whole space behind the aeroplane possibly may reveal an additional secondary train of transversal Waves in the intermedicongestion, we now face the technical problem of reclaiming some portion of that kinetic energy for the propulsion of the aeroplane before it is wasted by dissipation. In the systematic experiments of Mr. Wittemann with following aeroplanes, of which he has used as many as seven in tandem on the same machine, he has attempted to utilize the congestion of air trailing behind each single plane for carrying the following plane, but all the combinations he has tried and described in his afore mentioned paper have convinced him of the futility of such attempts and the only satisfactory results he has obtained, were those with following planes so spaced that each entirely cleared.

the space occupied by the congestion caused by the preceding plane. Therefore it does not seem the said congestion ever will serve for carrying another aeroplane riding on top of it, and indeed, if one aeroplane is mounted so as closely to follow another, the effect could not much differ from that resulting from merelyextending the preceding plane in its width backward, but this already was known to be of no benefit, there fore something else must be. tried in reclaiming the kinetic energy wasted in the congestion trailing behind an aeroplane, and this is the object of my present invention. I attain this object by replacing the aeroplane by a slatted grate similar to such used in window blinds. Fig. 3 shows a biplane built of two-such slatted frames, 1 on top, and 2 at the bottom. holding rows of parallel slats or blades' 3. The cross section of each vgrating may be straight, like Fig. 4, or

curved. like Fig. 5. with straight blades or vanes 3, or it may hold curved blades4, as shown in Fig. 5.

If an aeroplane is'plane, its portion in front is more affected by the air than that behind, so that the center of pressure lies in its fore half, and is shifting with varying pressure. 'In order to avoid the latter inconvenience curved aeroplanes are generally used. on which the pressure in the rear increases with an increasing angle of incidence and therefore automatically counteracts the shifting of the center of pressure, which with a grated aeroplane would not be necessary. provided all its proportions are correct. The action of the air on such a grat- .ing will be understood when looking at diagram Fig. 6, which is meant to show a portion of a longitudinal cross section to scale.

- The grate is supposed to move in the direction of the arrow, when at a proper angle of lncldence the several curved blades or vanes .4'will strike the air with the same force, provided the same amount of air caught between two adjacent blades at the bottom is discharged on top. By each blade or vane 4 the air in front of it will be. compressed and back of it rarefied, and since this effect will be stronger near the bottom, due to the mcreasedjcurvature, the compressed a1r in front. of every vane will rise, part of it streaming upward, hugging the blade and thereby maintaining a higher pressure on its downward surface than on its opposite, surface where the air pressure becomes reduced, and another portion will stream around the lower edge of the blade to the back side where the pressure becomes reduced. Since the whole frame moves in the direction of the arrow this latter portion of the air streaming upward around the lower edge of the blade, cannot hug to this blade, but when rising will strike the following blade, increasing the pressure on the same.

If therefore the succeeding blades in the grate are properly spaced, then always the same amount ofair will escape on top as there enters between the blades at the bottom, and while the air is scooped and violently struck by the blades at the bottom,

in order to obtain its compression, .it will, spending its energy as it rises by expansion, emerge on top without any proper-motion with regard to the outer air. If these conditions are fulfilled, no vacuum will be left to follow the soaring grate on top and not much compressed air underneath, and con- I sequently no congestion of air will be caused to trail the moving grate as with the aeroplane described in the foregoing, and all the .useful work of the propeller will be consumed in lifting the grating, without causing useless commotion and congestion of the surrounding air, through which power is wasted.

As afore mentioned, the width of an aeroplane is limited by its efliciency and that is chiefly due to the congestion of air" caused of. any suitable material, like bamboo, but

considering combustibility, it will be preferable to use sheet steel that can be worked into any proper shape and will facilitate the whole construction, "with corrugated blades. If a pliable fabric isused, replacing the blades by ribbons, the cross section of the grate may look like Fig. 7, where the upper edges of the single ribbons 5 are suspended on wires 6, "and the lower edges are held down by wires 7, while the sharp bends 8 indicate that these ribbons at, the angles 8 also are held back by wires. If a light and strong frame for the whole structure has been. built, within this frame a cubicalnet of wire may be rigged 'so that-every point of it can be reached from the outside for repairs, and in this cubical'net any suitable combination of parallel rows of blades, as

a-fore described, may be so mounted that the single blades a on top to parallel wires I 7 are fastened to 6, and

below to parallel wires 7. If by any suitable device the lower wires 7 are released, the pressure of the air will turn all the blades upward so as to form a closed solid roof.

The diagram Fig. 8 shows an isolated cubical mesh of the tridimensional net above described, EFGHTKLM being the corners of the cube. The adjustable corrugated blades 4,,of which there are shown only four to the mesh, but may be many more, are fastened at their upper edges to the wires 6 in such a manner that they can swing backward just enough to touch the blades behind when released, while they are held in open position. by means of the ropes 7 at their lower edges. These ropes the frame in the rear, while in front they wind around pulleys 10, mounted on shafts 11,and provided with levers 12, acted upon by the rope 18. It will be understood that when. this rope 13 is pulled upward, the ropes 7 tighten and draw all the blades 4 forward, while when the rope 13 is slackened, they swing back and shut the roof.

Still more simple it becomes with vanes of pliable fabric, like those in Fig. 7, if we dispense with wires folding the single r1bbone to the shape in the diagram. in this case no sharp bend 8 will appear, but each ribbon will bulge like a sail under wind,

and if the pressure of the air blows upward, they will close the grate, as will be understood by looking at the ribbon in the center of which the movable bend 8 is bound to 1 move on the are 9 of an ellipse having for foci the two points where the ribbon is tached to the two holding wires 6 and 7.

It has been long known that the lifting power of a soaring oblong aeroplane is greater when the plane moves with its longer side leading, due to the air reflected in front intercepting the air that strikes the plane behind, and therefore all aeroplanes are built much wider laterally than in the direction of flight. Further it had examination that these devices of other in-' ventors either had been conceived only in a crude way, similar to gratings T have sketched in Figs. 3, 4, and 5 of my drawing, and could not be built light enough to fly; or the peculiar shape they had fancied for their transversely extending narrow planes was erroneous. as can be shown with reference to the effect observed by Mr. Wittemann.

This effect, as describedin the foregoing, consists in the peculiar commotion of the air following every moving aeroplane and comprising a large amount of wasted energy. lln order to increase the efficiency of the flying machine this commotion, no matter what its kinetic character may he, must be reduced to a minimum, and how this is to be done, I already have described in the foregoing, but in order to distinguish my-invention from other contrivances T refer to Fig. 6 of my drawing.

The cross section of the blades there shown represents the quadrant of an ellipse and this peculiar shape has been selected for the following reasons. In order to out out the Wittemann effect, that is the stationary commotion A in Fig. 1, the air hit and displaced by any ofthe following blades at the bottom must be discharged on top at rest in relation to the surrounding atmosphere; and in order to obtain the greatest lifting effect, the possibly largest amount of air. must so be displacedby every blade.

From these two conditions follows that the curvature of every blade must be of such a nature that at its lower edge the tangent plane). to the cylindrical surface of the blade must be vertical, in order to strike most effectively the encountered air; and at its upper edge the tangent plane must be horizontal in order not to impel the escap ing air on top. The, quadrant of the ellipse shown in Fig. 6 meets both requirements, and besides the gradually changing curvature in the ellipse'causes the least friction in the rising current of the air hugging the blade. Therefore the quadrant of the ellipse appears to be the ideal cross section for the blade, and lwhile slight deviations from this shape, even a broken line shown in Fig. 7, may prove serviceable, a curve of reversed curvature for the cross section is faulty and being defective, it cannot be ef- 1. A. supporting member for flying ma chines comprising a plurality of following transversely extending blades, each of which being the inder.

2. A supporting member for flying i chines'comprising a plurality of following transversely extending cylindrical blades of pliable material, shaped and held in posiquadrant of an elliptic cyl- I two subscribing witnesses.

tion by sets of parallel horizontal 'wires,

strung on the frame of the machine in longitudinal and in transverse direction.

3. A supporting member for flying machines comprising a plurality of following transversely extending blades, held in position by a set of parallel longitudinal wires on top and by another set of parallel longitudinal wires at the bottom, strung on the frame of the machine; and a means for shifting the lower set of wires in relation to the upper set for the purposeof closing the spaces between adjacent blades in case the machine is dropping In testimony whereof I have signed my name to this specificationin'the' I OSCAR HERMANSON.

-Witnesss:

THEODORE A. HERRING, GERTRUDE C. WESSER.

presence of I 

